import sys
from collections import deque

def main():
    n = int(sys.stdin.readline())
    d = list(map(int, sys.stdin.readline().split()))
    x, y = map(int, sys.stdin.readline().split())
    
    target = (x, y)
    visited = {}
    q = deque()
    q.append((0, 0, 0))
    visited[(0, 0)] = 0
    
    while q:
        current_x, current_y, steps = q.popleft()
        
        if (current_x, current_y) == target:
            print(steps)
            return
        
        for di in d:
            max_diff = di
            for dx in range(-max_diff, max_diff + 1):
                for dy in range(-max_diff, max_diff + 1):
                    if max(abs(dx), abs(dy)) != max_diff:
                        continue
                    new_x = current_x + dx
                    new_y = current_y + dy
                    if (new_x, new_y) not in visited or steps + 1 < visited[(new_x, new_y)]:
                        visited[(new_x, new_y)] = steps + 1
                        q.append((new_x, new_y, steps + 1))
    
    print(-1)

if __name__ == "__main__":
    main()